The Pascagoula gas plant experienced a fire and explosion in June 2016 caused by the failure of a brazed aluminum heat exchanger (BAHX) due to thermal fatigue. Previous process hazard analyses in 1997 and 2009 had identified BAHXs as a risk and recommended procedures to minimize damage or replacing them. However, later analyses in 2013 and 2015 downplayed the risks, focusing only on the financial costs of repairs based on the plant's experience with leaks rather than safety hazards. The 2016 incident resulted in a community evacuation and over $10 million in expenses, highlighting the normalization of risk that had occurred over time.

1. Pascagoula Gas Plant Incident
Sanjeev Saraf
CSB report: https://www.csb.gov/assets/1/6/final_case_study_-_enterprise.pdf

2. Facility
• Pascagoula gas plant
• Gas plant receives condensate from Destin pipeline in deepwater GoM
• Gas (C1-C4) separation from NGL using cryogenic process
• Brazed aluminum heat exchanger (BAHX), which allows for the transfer of heat between
different process
• Susceptible to thermal fatigue. Weakening of braze joints between fins and parting sheets

3. Design PHA
• 1997 (design-stage): team did not expect the hazard to have a public impact and
anticipated only minor damage and downtime. Team assumed the likelihood of
thermal shock to be once every 50 years and labeled it as a “medium priority,” for
which the company recommended that “serious and appropriate actions should be
taken.” In response, the PHA team recommended developing procedures for the
BAHXs’ various operating modes (e.g. start-up, shutdown) to minimize the
likelihood of thermal shock events.

4. PHA Revalidation
2009: “high impact health/safety incident” with the potential to cause (1)
“permanent partial disability(ies),” (2) “several non-permanent injuries or health
impacts,” and (3) “days away from work.” As a consequence, the PHA team
recommended evaluating the replacement of the BAHXs with a different
exchanger design.

5. PHA Revalidation and follow up
2013: The 2013 PHA revalidation no longer identified health and safety consequences associated with the
exchangers. Instead, the listed potential consequences mirrored the plant’s experiences with leaks. Exchanger
repairs in the range of $60-150-k. The safeguards for minimizing BAHX damage identified in the PHA were
metal temperature sensors, operator intervention, and operating procedures.
2015: A plan to change them out within 3 years to “ensure equipment integrity.” Justification for the plan stated
that “cyclical operation causes small cracks on heat exchangers. Rapid cooling or heating of the brazed
aluminum heat exchangers has the potential to create small cracks around support pads. Small cracks result in
weeps of gas out. Potential for personnel injury is minor. Cost associated with repairs and downtime. Repair
costs vary from $80 thousand onsite to $100 thousand offsite”

6. BAHX failures – 9 failures in 11-years (18-operating years)

7. Incidents
• Incident occurred on 27 June 2016
• Operators initiating controlled shutdown
• Fire and explosion reported at 11:22 pm
• BAHX failure from thermal fatigue
• 13 different ruptures of piping and equipment during the course of the
incident
• Community evacuation
• $10.4 million of expense due to fire response activities; $7.1 million non-
cash activities

8. BAHX failures

9. BAHX failures

10. Comparison of the Train-B (top) and Train-A (bottom)

11. Be aware of normalization of risks based on past-experience.
Sanjeev Saraf
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